Its not too weird honestly (The Ikenga set). And COR doesn't get near the natural Ranged Attack that RNG does, so COR doesn't often benefit from the +PDL on Malignance when shooting. The extra ranged attack when compared against Malignance set combined with still retaining +PDL should improve white damage because now on COR we'll see that PDL in action.
Not to mention, these days I pull hate when shooting a LOT more on COR than RNG, between the tools/abilities RNG gets for hate mitigation/transfer that COR does not. That -enmity can really matter.
In terms of specific pieces- I think the head should be an easy option for Wildfire sets for those without a top notch Herculean Helm augment- once its RP'ed. The TP bonus on the body is strange- I don't expect it to beat AF+3 body and its 10% WSD, and certainly shouldn't beat Relic+3's high MAB for magical WSs. It may at capped attack be best for Last Stand due to the +PDL, but honestly I don't know. The feet could be interesting if able to stand at a real True Shot distance when stacked with Nisroch and Oshosi legs
AND Tripleshot is down- no way I'd give up Oshosi feet.
In terms of an Armageddon Aftermath set, again it'll be a discussion for tripleshot up/tripleshot down. While up, I don't see any of this gear being valued for COR. But while down, some select pieces mixed in to a crit set could be good. I do a similar thing already on RNG when using Annihilator by mixing in 1-2 pieces of Malignance to take advantage of the +PDL- and the ranged attack on Ikenga should mean taking advantage of that stat should be easier.